Maintaining the constancy of internal environment of an organism ishomeostasis. Water plays an important role in maintaining homeostasis which are mentioned below;

1. Water dissolves gases thus, helps in exchange and transportation of oxygen and carbondioxide.
2. Water , when excreted removes water soluble toxins from the body.
3. Water helps to remove excess heat from body in form of sweat that helps to regulate body temperature.

Amino acids are molecules that combine to form protein. Some of the important function of amino acids are;

a.) Amino acid are building block of proteins .

b.) Amino acids are amphoteric(able to react both as an acid and a base), thus they can buffer in solutions, resisting change in pH .

c.) Histidine are found in active site of enzymes where it causes making and breaking of bonds.

d.) Cysteine links chain together by forming disulfide bonds.

e.) The non- protein amino acids are useful compounds...

Watson and Crick described DNA as a double helix that contained two long, helical strands wound together. In their model, each DNA strand contained individual units called bases, and the bases along one DNA strand matched the bases along the other DNA strand. Some characteristics of this DNA are,

a.) DNA consists of about 10^10 deoxyribonucleotides.

b.) The diameter of DNA is about 20 Angstrom.

c.) Nitrogen bases are of two types: purines (Adenine and Guanine) and pyrimidines (Cytosine and...

Polysaccharides, or polycarbohydrates , are the most abundant carbohydrate found in food which provides very important dietary elements for human nutrition. It can be starch , cellulose or glycogen. They are important class of biological polymers. It's function in living organism is generallly either energy storage or structual support.